@bg-color:#b7d4a8;
*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

#main{
  width: 360px;
  height: 420px;
  background-color: @bg-color;
  margin: 100px auto;
  border: 10px solid black;
  border-radius: 10px;
  font-size: 14px;
}